Process for vaporizing and treating materials under high vacuum



Nov. 18, 1941. I c. G. FERRARI ETAL 2,262,996

PROCESS FOR VAPORIZING AND TREATING MATERIALS UNDER HIGH VACUUM Filed Sept. 6, 1938 5 Sheets-Sheet 1 1 [nvenL oru C/MELQS G; FERRARI LEJrE/e EBQRCHAKDT p l Wad, 4mm $24.2.

' ATTOAQNEYS Novo 18, 1941.

C. G. FERRARI ETAL PROCESS FOR VAPORIZING AND TREATING MATERIALS UNDER HIG H VACUUM Filed Sept. 6, 1938 3 Sheds-Sheet 2 Nov. 18, 1941. 2,262,996

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Patented Nov. 18, 1941 PROCESS FOR VAPOBIZING AND TREATING MATERIALS UNDER HIGH VACUUM Charles G. Ferrari and Lester F. Borchardt, Minneapolis, Minn., assignors to General Mills, Inc., Minneapolis, Minn., a corporation of Delaware Application September 6, 1938, Serial No. 228,720.

4 Claims. (Cl. 204-156) This is a continuation-in-part of our application Serial Number 725,408, flied May 12, 1934.

Thisdnvention relates to process for vaporizing and treating materials under vacuum, and has particular reference to a process for continuously vaporizing and treating ergosterol or other activatable substances under high vacuum in order to impart thereto the physiological property of curing rickets.

A general object of the invention is to provide a simple and efflcient type of process wherein a large supply of ergosterol may be gradually vaporized and treated under vacuum conditions,

and the invention furthermore contemplates the provision of a process of this character which is automatic in operation.

Continued heating of ergosterol for long intercordingly another object of the invention to provide such a process wherein it is unnecessary to keep the main source of ergosterol heated in order to continuously form ergosterol vapor, and wherein it is unnecessary to keep the collected material in heated condition.

These and numerous other objects of the invention will become more readily apparent upon a detail study of the accompanying drawings and specification, wherein only one type of apparatus for use in carrying out the invention is illustrated by way of example, together with the appended claims. 7

Referring more particularly to the drawings:

Figure 1 shows a rear elevation of one form of the apparatus;

Figure 2 is a vertical longitudinal cross-section along the lines 2-2 of Figure 1;

Figure 3 is a fragmentary cross-sectional view disclosing the details of the positively acting mechanical mechanism for supplying ergosterol from the reservoir to the inlet leading to the vaporizing chamber;

Figure 4 is a fragmentary cross-sectional view of the furnace for heating the vapor treatment chamber, showing the relative positions of the heating elements and the inlets for the electrical activating coil;

Figure 5 is a detailed cross-sectional view showing a bearing of a screw conveyer for feeding ergwterol from the reservoir; and

Figure 6 is a detailed view showing a ring used at the outlet of the vapor treatment chamber to collect condensate and prevent choking.

In the drawings, numeral 2 represents a table or other support that may rest upon rollers as shown, which has mounted thereon by means of I vals tends to promote decomposition and it is acpipe supports a furnace generally designated at 4, and an upper or super platform 6. Beneath the furnace, the table is-cut away to form an opening 8 and beneath this opening there is mounted a sub-platform III by means of pipe supports i 2.

The oven 4 is here shown as substantially circular in cross-section and has a composite peripheral wall formed of an inner layer of refractory material I4 and an outer layer of magnesia asbestos covering I6 which is covered by means of cloth it. This wall is preferably formed with anopening 20 'closed by a window 22 of mica or other suitable substance through which the operator may observe conditions within the oven. The furnace is furthermore provided with top and bottom composite walls generally designated at 24 and 26, each formed of an inner layer 28 and a spaced outer layer of suitable insulating material 30 and 32 such as transite. It will be noted that the outer layer of 'transite 30 at the bottom of the oven is substantially coextensive in size with the walls of the oven but the upper transite member 32 extends beyond the side of the oven to support a heater 34 which is used for a purpose more specifically pointed out hereinafter. Adjacent the walls of the oven and parallel to its axis are a series of vertically arranged and uniformly spaced electrical heating elements 36 which extend only to a spaced distance below the top of the oven and which terminate at a spaced distance above the bottom of the oven.

The numeral 40 designates generally a tube formed of glass or other suitable material having a main upright portion 42 constituting a vapor treatment chamber which is open at the bottom, and a downwardly bent top portion 44 forming a vaporizing chamber 50 which has a surface 46 upon which material to be vaporized may be dropped through the vertically disposed inlet neck 48 of the vaporizing chamber. As clearly shown in Figure 2, the tube 40 is centrally locited with respect to the furnace 4 and extends through the top and bottom thereof, the vaporizing chamber 50 being located above the furnace and at the top of the heater 34, and the vapor treatment chamber 42 being disposed inside of the furnace. Numeral 52 designates an electrical heating coil embedded in asbastos or other suitable material for heating the tube 40 between the vaporizing chamber portion 50 and the vapor treatment chamber portion 42 which is located within the furnace 4. Numeral 5| designates a heating coil also embedded in asbestos for heatin; the inlet to the vaporizing chamber. The

elements 86 and the coil 62 are connected to a source of energy in any desired manner for continuous energization while the apparatus is in operation. The heating coil 5| is arranged to be only periodically energized, as for instance for a period of twenty seconds every five minutes, by means of a circuit connected to any suitable source of energy and including the timing device generally designated at 63 for automatically making and breaking the same.

The super platform generally designated at 6 comprises a lower supporting member 54 in the form of a hollow rectangle, and a cover member 56 partially coverin the same which is secured thereto and provided with an enlarged opening 58. Another cover member 60 is hinged to the fixed cover member 56 and may be swung open to facilitate removal of the tube 40. Secured to ,the top of the member 56 at either side thereof there is a track 62 upon which is slidably mounted a supporting plate 64 as clearly shown in Figure 1. The blocks 66 on either side of the opening 58 serve to further support the plate 64 as will be apparent from Figure 1.

Suitably mounted upon the slidable plate 64 is a reservoir for ergosterol designated at 68 which may be made of metal or other suitable material and an electric motor I0, together with mechanism driven by the motor for feeding ergosterol from the reservoir. The reservoir is provided with a removable top I2 to enable admission of fresh quantities of ergosterol to the reservoir from time to time, but which top can be closed with a vacuum tight joint. The lower portion of the reservoir communicates by means of a vacuum tight joint with a conduit I4 in which a screw conveyer I6 is rotatably mounted. The left hand end of the conveyer 16, referring to Figure 3, is mounted in a graphite bearing I8 held in a plug 80 which is screw-threaded and sealed in one end of the conduit 14. The other end of the screw conveyer rests in a recess of a conical element 84-which rotates in a bearing 86 that is sealed to one end of the conduit I4 and has a pin and open slot connection 82 therewith as clearly shown in Figure 5. Rotating member 84 has a pin and open slot connection 88 with a universal joint 90 that is connected to a second universal joint 92 which in turn is connected to the drive shaft of the motor I0. For the purpose of lubricating the bearing 86 and providing a vacuum tight connection thereat, the bearing is formed with a connection to a collapsible tube 94 containing suitable grease as shown in Figure 3 which may be squeezed from time to time for purpose of lubrication. In order to prevent the grease from working down into the conveying I mechanism, the rotating member 84 is provided with a peripheral groove 96 as will be evident from Figure 5.

As clearly shown in Figure 3, the conveyer conduit 14 is provided with a discharge opening II at its lower surface, and adjacent the end of the conduit remote from the reservoir. This 1 opening is connected to the vertical inlet neck 48 of the vaporizing chamber 50 by means of a I suitable vertical conduit generally designated at h 88 and in this case formed of an upper metallic portion I00 of copper or the like which is secured to the opening II by means of a vacuum tight joint at one end and which is secured by means 1 of a vacuum tight joint at its other end to a section of glass or the like I02 which connects 1 under vacuum seal with a similar section I04 that 3 in turn connects with the vertical inlet neck 48 of the vaporizing chamber by means of a vacuum tight joint. The metallic portion I00 of this vertical'conduit is provided with a suitable cooling jacket I08 through which water or other suitable cooling fluid may be continuously'circulated, preferably through flexible connections.

The connection shown and described between the conveyer conduit I4 and the inletneck 48 is rigid. Preferably this connection is made flexible with some suitable joint in any desired manner as for example by substituting a metallic tube section having flexible metallic Sylphon bellows formed integrally therewith for the tube chamber, it being noted that the position of this inlet neck may vary with different tubes. While no mechanical adjusting means for the plate 64 are shown it will be readily appreciated that any suitable type may be provided if desired.

The lower end of'tube 40 extends into and has a vacuum tight connection with a collecting vessel I I0 which may be made of metal or other suitable material and which rests upon a plate member II2 having three supports II4 resting on the sub-platform I0. These supports II4 are screwthreaded as shown to enable vertical adjustment. In addition the supporting plate 2 is provided with three radially spaced upstanding lugs H6 having screw-threaded openings receiving screws I I8 for horizontally positioning the receptacle H0 upon its supporting plate. The tube 40 is further provided with a pair of vacuum tight outlets I20 each formed with a suitable trap I22 which are cooled in known manner as for instance by solid carbon dioxide and acetone, and connected with any suitable vacuum producing means I24.

A coil of electrically conductingmaterial I30 such as copper or the like is slightly spaced from and surrounds the vapor treatment chamber 42 within the furnace 4 and directly opposite the heating elements 36 and with its axis coincident with that of the oven. This coil is provided with leads I32 and I34 extending outside the furnace and connected to any suitable source of high frequency and high voltage current I36. As shown in Figure 4, the leads are preferably passed.

through the walls of the furnace at a point intermediate .adjacent heating coils 3'6 inasmuch as arcing might result if these leads were placed too close to the heating elements.

A non-continuous ring I40 which is made of .any suitable metallic spring material such as inner walls of the tube and remain upon release of the pressure. As shown in Figures 2 and 6. the upper edge of the ring is preferably beveled the reservoir.

317-140 "so as to facilitate reception of condensate from walls of 'thetuber The ring may be coated with any desired metal. Also itmaybe of glass or the like formed integrally with the tube but a' removable spring metal ring as above described is preferable inasmuch :-as cleaning is facilitated.

- Referring again to- Figures 1 and 3-it will be observed that a by-pass conduit I50 connects the top of the reservoir 60 with conduit" at a point beyond its discharge opening with respect to the reservoir, for the purpose of readily producing a condition of high vacuum above the material in Otherwise air might gradually seep through the ergosterol into the system. This conduit of course has vacuum tight connections at the points indicated and it is of course obvious that all of the other connections heretofore mentioned in the system in which the ergosterol is contained and through which it passes must also be vacuum tight.

In operation of the process, the reservoir 50 is filled with ergosterol or other activatible material in substantially powdered or granular form and the lid 12 is then closed with a vacuum tight seal. The vacuum producing means I24 are set into operation until a very high vacuum, i. e. of the order of from 5x10- millimeters of mercury to 1x 10- millimeters of mercuryis obtained although it will be appreciated that this range of vacuum .is subject to a great deal of variation, especially in the direction of higher vacuum. The heater 34, the heating coil 52 and 36 are energized in order to heat up the tube 40. When the system has been thus evacuated and the tube heated, high frequency and high voltage current is applied to the coil I30, the motor I is placed in operation, cooling fluid is circulated through the cooling jacket I05, and the timing device is set in operation to periodically energize the coil 5| for a purpose more fully set forth hereinafter.

The motor rotates the screw conveyer 16 which positively operates continuously to supply small quantities of ergosterol to the vertical conduit 98 leading to the vaporizing chamber 50. As the ergosterol particles strike the vaporizing chamber wall 46 they vaporize very quickly and the vapors thus formed escape into the vapor treating portion 42 of the tube 40 wherein they are subjected to an electrodeless discharge set up by the coil I30. The vapor is maintained in this state during its passage from the vaporizing chamber 50 to the vapor treatment chamber 42 by means of the coil 52, and is maintained in the vapor state while passing through the zone of the coil I30 by means of the heating elements 36. After the vapor passes the bottom of the heating coils 36 and reaches the bottom of the furnace it condenses and collects as a liquid upon the ring I40. .As shown in Figure 2 this condensate drops from the end of the depending reduced portion 4 into the receptacle I I0, wherein it solidifies, without engaging the side walls of the lower portion of the tube 40.

In the absence of heating coil 5| there might be a tendency for vapor to condense and clog up the inlet to the vaporizing chamber. However, any collection of condensate which there occurs is periodically heated to the melting point by the intermittently operating coil 5| and dropped into the vaporizing chamber, which automatic means for intermittent operation are shown. Manual means may of course be used if desired.

The operation will continue without choking or cloggingfor an indefinite period'of time, i, e. until the supply of'ergostero'l within the reser -voir is exhausted, after which the operation of degree of antlrachitic potencyis imparted to the 3 ergosterol by treatment thereof with the electrodeless discharge in the vapor state and the material collectedin receptacle ||0 may therefore be used in the usual manner for preventin and curing rickets. Y I

While we have shown the vapors in the vapor treatment portion of tube 40 as subjected to an electrodeless discharge, these vapors may, if desired, be subjected to other forms of treatment for purpose of activation at this point. For example, the tube 40 may be made of quartz or other material capable of transmitting ultraviolet and a source of this energy may be projected upon the vapor treatment portion of the tube. Again, the vapors may be subject to other forms of electrical treatment such as a high frequency discharge between spaced electrodes whether internal or external with respect'to the tube.

It will be observed that the main supply of ergosterol in the reservoir is not maintained in heated condition at any time during the operation, and that the collected, activated ergosterol is also not maintained heated whereby decomposition due to heating is substantially, eliminated.

In carrying out the process it is advisable to preheat the commercial ergosterol used in a vacuum oven at temperatures sufllciently high to remove any residual solvents but not high enough to cause decomposition. Ergosterol which is so treated not only is a freely flowing product but does not give rise to objectionable vapors which might spoil the vacuum and contaminate the process. In fact the latter reason is the principal I the antirachitic, vitamin D property.

As will be evident from the foregoing, any desired type of treatment may be employed and the process may be used in the treatment of any desired material for any desired purpose in addition to use in the manufacture of vitamin D, the invention being of the scope indicated in the appended claims.

We claim as our invention:

1. The continuous flow process of vaporizing and treating ergosterol, which comprises gradually feeding such substance in finely divided form and at a temperature below its melting point from a charge thereof into a heating and vaporizing zone, quickly vaporizing all the substance under high vacuum' substantially as fast as fed, activating the vapors to impart thereto the antirachitic property, collecting the resulting material at a temperature below the melting point thereof, and maintaining the substance her from the top and therein quickly vaporizing the same, withdrawing the vapors as fast as formed under high vacuum from the side of the vaporizing chamber, activating the vapors, and collecting the resulting antirachitic material, said ergosterol being vaporized substantially as fast as fed. 3. A continuous flow process of producing vita min D from material susceptible of activation to impart thereto the antirachitic principle, which comprises passing a continuous stream of such material under high vacuum in finely divided form and at a temperature below the melting point thereof to a heating and vaporizing zone, heating and quickly vaporizing substantially all the material of said stream, and then activating the vapor thus produced to give it the.antirachitic property by imparting energy thereto, said material being vaporized substantially as fast as fed.

4. A continuous flow process of producing vitamin D from material susceptible of activation to impart thereto the antirachitic principle, which comprises providing a continuous stream of such material under high vacuum in finely divided form and at a temperature below the melting point thereof and passing the same to a heating and vaporizing zone, heating and quickly vaporizing the material of said stream substantially as fast as fed, and then passing an activating electrical discharge through the vapor-(thus produced to impart the antirachitic property thereto,

CHARLES G. FERRARI. LESTER F. BORCHARDFI. 

